In response to RFA MH 94009, UNO-CAP, this application proposes a 5-year study of 3900 4 to 17 year olds--3000 from the general population and 900 identified as in need of psychological assessment or treatment from six service sectors (mental health, juvenile justice, child welfare, education, general health, and substance abuse). The study will determine rates of mental disorders and impairments, availability and use of mental health services, impediments to service usage, costs of service use, and outcomes of use or lack of use. The research, entitled Missouri Child and Adolescent Project (MOCAP), would be conducted in the "Heartland of America" in areas with above average rates of mental illness risk indicators. The three specific target sampling areas selected are: the racially mixed rural Bootheel area of Missouri, and two areas in St. Louis City--one comprising the St. Louis proposed Federal Empowerment Zone (which would mean a major infusion of resources to the City) and one outside the Zone. The methods will build upon those of the NIMH-funded MECA studies. Suggested are a number of new methods and interests for a multisite study of children and adolescents such as: assessing mental disorder among 4 to 8 year olds with direct interviews; evaluating changes in mental health status over time; determining the cost of mental health services provided to children and adolescents; describing the patterns of referral to mental health services, barriers to care and satisfaction with services, and evaluating whether use is associated with perceived need. In addition, the MOCAP team proposes a study of the role of exposure to violence at home, in the media, and in neighborhoods on changes in mental health status; an investigation of the association between an adult informant's mental health status with their report about the child, and a parallel study in Ontario where the health payment system is different. A 2-year followup assessment is proposed with another wave envisioned as part of a continuation. This study would extend the research of an investigative team with great experience and interest in conducting large-scale, multisite epidemiologic studies, in developing psychiatric assessments, in nosological issues of psychiatric disorders, in assessing the reliability and validity of assessments, and in health services research. In addition, collectively, the team has the essential local and statewide networks needed for this exciting endeavor.